Multiple media outlets reported that 25-year-old Caleb Brad Matlock pleaded guilty in Moncks Coroner on Monday to killing 18-year-old Dana Woods and 22-year-old June Guerry.
Their bodies were found in the Francis Marion National Forest in August 2012.
Matlock's plea came as he was to face trial on two counts of murder, two counts of possession of a gun during a violent crime, armed robbery and third-degree arson.
Matlock will not be eligible for parole.
Matlock apologized to the families of the victims and said he knew the apology was inadequate.
A co-defendant, 25-year-old Arthur Ray Chavis of Cordesville, is awaiting trial.